Is Extremely Loud and Incredibly Close a True Story?

Extremely Loud and Incredibly Close is a new movie which is said to be based on a true story depicting the events on 9/11 from the point of view of a 11 year old kid. However, Extremely Loud and Incredibly Close could be another movie said to be a true story but end up being an exaggerated fake, as they also add unreal scenes or facts to movies. I think they did that with that movie about the 9/11 plane, some of the stuff in the movie was real but others were just made up. What do you think? Is Extremely Loud and Incredibly Close based on a true story?

Yes, Extremely Loud and Incredibly Close is a true story and it's going to be quite emotional for the American audience I guess.
That day pretty much marked all Americans and everything changed after that.
In the movie, Tom Cruise will play one of the lead roles so I'm very excited to see Extremely Loud and Incredibly Close, I'm pretty sure it must be a true story. Why do they make up something like this? 9/11 is quite important and many movies have been made about it, all of them are real. Extremely Loud and Incredible Close is a true story and it must be worth it!